Conventionally, there is known a microfluidic chip for supplying a plurality of liquids to a minute passage, thereby mixing the liquids and causing this to react.
In the minute passage, a width and a depth have small size of several micrometers to several hundred micrometers. In addition, a flow rate of the liquid is also reduced in the minute passage. For this reason, in the minute passage, Reynolds number of a fluid is equal to or smaller than several hundreds and the same turbulent flow control as that in the conventional reacting device cannot be obtained but a mode for a laminar flow control is obtained.
Under the laminar flow control, different types of liquids are mainly mixed by a molecular diffusion over a contact interface between the respective liquids. A behavior of the mixture in the liquids is defined by a thickness in a diffusing direction of the liquid (a distance at which the different types of liquids are to be diffused to obtain a uniform concentration=a diffusion distance), and furthermore, a long time is required for the mixture.
Therefore, there is proposed the technique in which two types of liquids are divided into a plurality of flows respectively and the flows are alternately arranged and supplied so that a contact area between the liquids of the different types is increased to promote a mixture of the liquids (for example, Japanese Patent Application Laid-Open No. 2006-43617 and the like). Moreover, there is proposed the technique in which different types of fluids are introduced from a lower part of a cylindrical mixing vessel so as to generate a rotational flow, thereby promoting a mixture of the fluids (for example, Japanese Patent Application Laid-Open No. 2006-167600 and the like).